By Dhel Nazario
A demonstration of Philippine microsatellite Diwata 2’s Amateur Radio Unit (ARU) was recently showcased by members of the Space Technology and Applications Mastery, Innovation and Advancement (STAMINA4Space) Program which can be used in times of disasters where lines of connection are unavailable.
The amateur radio unit (ARU) payload onboard the microsatellite Diwata-2 is a spaceborne module targeted for amateur radio communications and disaster/emergency response.
Designed and manufactured in the Philippines, it features voice repeater and APRS text
messaging capabilities. Because of the ARU, Diwata-2 is now designated by the Radio Amateur Satellite Corporation (AMSAT) as Philippines-OSCAR 101 (PO-101).
The ARU is a spaceborne receiver/transmitter device which is placed into a 600 km orbit.
Hence its high altitude means that any ham operator can access Diwata-2 and communicate with another station up to all over the Philippines and even internationally.
The sun-synchronous orbit of Diwata-2 means a regularly occurring passes around noontime and midnight. Thus, you know when to access the ARU for calls and messages.
During the demonstration, the team was able to contact partners from Dagupan, Pangasinan and also attempted to make radio contact in Japan with the use of an improvised antenna made from PVC pipes.
To be able to use ARU, one must first register as an amateur radio operator and will need a VHF/UHF handheld transmitter, directional antenna (homebrew or bought in stores), orbit tracker app is recommended.
In setting the transmitter, downlink (receive) frequency of your transmitter should be at 145.900 MHz. Uplink (transmit to Diwata-2) frequency is at 437.500 MHz with a tone of 141.3 Hz.
Search the horizon for the location of Diwata-2. Use an orbit tracker for a faster and more accurate search. Point the antenna to the current direction of the satellite and wait for signal downlink. When the signal is received, you are ready to transmit. Listen first for ongoing calls before pressing the push-to-talk (PTT) button in your transmitter.